Build thread on the GT-VX2 Explorer.

NoWingsAttached

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The Cl max of a symmetrical airfoil with infinite aspect ratio is near18 degrees.
An aspect ratio of 4 increases this angle by about Cl / π. A (radians) i.e 4 degrees.
Turning a monobloc rudder beyond 22 degrees appears to me counter productive to stop a yaw.
No reference to AS. I think you are talking about air speeds in excess of 60 MPH, and at 45 MPH this math doesn't hold up.
 

NoWingsAttached

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You realize of course that "GT" stands for Greg Taylor. :cool:
 

Jean Claude

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The transverse force that can be produced by your monoblock surface is given by the formula known to all aerodynamicists:
F = 0.5 ρ * s * v² * cL
If the Reynolds Number is only 800,000, then cL is maximum when the A.o.A is about 18 degrees .
This is what the NACA report n° 610 shows, fig 4, for example:

Sans titre.png

This angle is gived for an infinite aspect ratio.
Whereas the rudder has an aspect ratio of about 4.
l must then add the angle induced under Prandtl's theory discovered in 1911
Induced angle (radians) = cL / π*A Hence 4 degrees for cL = 1.2
So, 22 degrees gives the maximum result and 35 degrees gives clearly less (observe the NACA curve)

Have the laws of aerodynamics been repealed recently?
 
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jm-urbani

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The Cl max of a symmetrical airfoil with infinite aspect ratio is near18 degrees.
An aspect ratio of 4 increases this angle by about Cl / π. A (radians) i.e 4 degrees.
Turning a monobloc rudder beyond 22 degrees appears to me counter productive to stop a yaw.
hello jc, thanks,
is it because beyond 18° the profile stalls ?
I will limit the swing to 22° each side so
bonne soirée
jmi
 
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Jean Claude

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About 500 h (FW + ultra light)
Yes, when the angle of attack becomes too large, the airflow no longer remains attached to the dorsal wall and lift decreases. Fast or slow speed doesn't change this. Just a matter of angle.
 

Resasi

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Thank you Jean Claude that was most informative.
 

jm-urbani

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salut , et merci encore, donc je fais quoi donc sur mon petit dernier , je limite à 18° de chaque coté ?

in english :

JC what do I do on my new baby ? do I limite the tall tail swing to 18° each side ?

cheers

jmi
Leigh sorry for spaming ur thread
 

Resasi

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No worries JM, the information elicited was very interesting to me.
 

Jean Claude

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22 degrees on each side if aspect ratio is 4 are sufficent
 
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